Perhaps you should try some spelling variations:
drugs studied » drugs studies, drug studies, groups studied
der filosofia » de filosofia, e filosofia, di filosofia
na literatura » la literatura, a literatura, a literature
filosofia na » filosofia da, filosofia la, filosofia n
tests drugs » tests drug, test drugs, testing drugs
studied der » studie der, studien der, studies der

You may be able to get more results by adjusting your search query.

• Adding a wildcard symbol may retrieve word variants: tests drugs studied der filosofia na literatura*.